Various types and arrangements of units are previously known in this art in conjunction with optical range finders which are included in, for example, proximity fuses for missiles, projectiles and other launchable units.
One such optical range finder operates with transmitter and receiver units included in the unit in question. The optical radiation departing from the transmitter is to be reflected on a target located in the transmission direction and back towards the receiver. Depending upon the distance of the target from the unit, the reflected radiation will impinge upon the receiver at different angles of incidence.
The transmitter must be provided with a power which permits reflection and purposeful reception of the received signal when the target is located at maximum range for which detection is possible.
This implies, inter alia, that, on target reflection on targets which are closer than the maximum range, there will be obtained an over-dimensioned incoming signal from the detector device. This entails problems not least because of the so-called return dispersion.